cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A368019 a(n) is the permanent of the n-th order Hankel matrix of Catalan numbers M(n) whose generic element is given by M(i,j) = A000108(i+j+1) with i,j = 0, ..., n-1.

Original entry on oeis.org

1, 1, 9, 979, 1417675, 28665184527, 8325587326635565, 35389363346700690999467, 2230867495754739989535874468003, 2106171270085074740753132799048111935155, 30007898337707083458776293190436074888346472515407, 6491219550166075876771081259839537013093735814742318424677245
Offset: 0

Views

Author

Stefano Spezia, Dec 08 2023

Keywords

Examples

			a(4) = 1417675:
   1,  2,   5,  14;
   2,  5,  14,  42;
   5, 14,  42, 132;
  14, 42, 132, 429.
		

Crossrefs

Programs

  • Mathematica
    Join[{1},Table[Permanent[Table[CatalanNumber[i+j+1],{i,0,n-1},{j,0,n-1}]],{n,11}]]
  • PARI
    C(n) = binomial(2*n,n)/(n+1); \\ A000108
    a(n) = matpermanent(matrix(n,n,i,j,C(i+j-1))); \\ Michel Marcus, Dec 09 2023

Formula

Det(M(n)) = 1 (see Mays and Wojciechowski, 2000).